There are reasons so many humans feel comforted by hugging. Like a massage, it “involves stimulation and pressure receptors, and when that happens, the whole nervous system slows down and stress hormone is reduced,” says Tiffany Field, director of the Touch Research Institute at the University of Miami School of Medicine. Still, for some, hugs induce stress more than they relieve it. When Sam Zelinka, a federal-government research scientist based in Madison, Wis., gets a hug from anyone other than his wife or kids, he gets the same feeling as when a stranger stands too close to him. And while Zelinka, 38, isn’t about to “spray paint a T-shirt and march in the streets yelling about no hugs,” he’s not exactly looking forward to one from anyone but his parents. “The people that hug me, I’m like, faced into their chest,” says Shantal Martin, a 27-year-old opera singer and influencer, who’s about 5-foot-2. When she left New York City in August to visit her family in Barbados, she found herself relieved at her relatives’ cautious distance in greeting her. “I was like, ‘This is great. I’m not being smothered by any of my aunts’ perfumes? Perfect.’ ”